Most instruments for characterizing a material of interest rely on indirect measurements of a property of interest. Typically, there is an assumed functional relationship between a measured quantity and a property of interest. Thus, for example, there is a linear relationship between the mass and the weight of an object. Accordingly, a simple calibration of a scale allows the mass of an object to be inferred from a measure of the object's weight.
Some instruments have more complex responses. Thus, for example, the electric potential of a thermocouple is a non-linear function of the thermocouple temperature. Since thermocouples are well characterized, a polynomial function may be used to convert the thermocouple output into a temperature. Thus measurements performed by techniques that are well-understood or well-characterized, may be used to a high degree of accuracy.
However, some instruments may have responses that are not understood well enough to generally compensate for biases in the instrument response. Thus, for example, if certain effects alter the output of an instrument and are not taken into account, then the use of the instrument may produce inaccurate measurements.
There exists a need for methods and systems to provide for improved accuracy of measurements having complex responses. Such methods and systems should provide improved accuracy by not utilizing derivatives of measured values.